1. Field
The present disclosure relates generally to antennas and, in particular, to antennas used to identify information about objects. Still more particularly, the present disclosure relates to using an antenna system to identify a height of a target object.
2. Background
An antenna is an electrical device that couples electromagnetic waves to an electrical current that may be used by a transmitter and/or receiver. In other words, an antenna may be used to transmit and/or receive electromagnetic waves. These electromagnetic waves may be used to detect objects.
For example, radar systems use antennas to determine information about objects. This information may include range, altitude, direction, speed, and other information. This information may be obtained for objects, such as, for example, an aircraft, a ship, a spacecraft, a missile, a weather formation, a train, and/or other suitable types of objects.
In a radar system, the antenna is used to transmit electromagnetic waves towards a target object. When the electromagnetic waves encounter an object, a portion of the electromagnetic waves may bounce off the object. The portion of the electromagnetic waves that bounces off of the object may be referred to as scattered electromagnetic waves. These scattered electromagnetic waves may be received by the antenna and used to identify information about the object.
Many different types of antennas may be used with radar systems. Some examples of different types of antennas that may be used include a parabolic reflector, a slotted waveguide antenna, and a phased array antenna. A parabolic reflector is an antenna with a dish having a parabolic form used to transmit electromagnetic waves in the form of a beam. Another type of antenna is an antenna with a slotted waveguide. This type of antenna also is configured to generate electromagnetic waves in the form of a beam.
A phased array antenna is typically comprised of individual antenna elements that are electronically controlled to generate electromagnetic waves in the form of a beam. With a phased array antenna, the steering or direction of the beam may be controlled electronically rather than by physical movement of the antenna itself.
Different antennas have different advantages and disadvantages. For example, some antennas may require more power to transmit electromagnetic waves than other antennas. Different antennas may have different frequencies at which desired levels of performance may be provided in transmitting and/or detecting scattered electromagnetic waves. As another example, different antenna designs may have constraints in terms of their placement, shape, size, and/or weight. Further, with directional antennas, the beams that may be formed may have limited angles.
Therefore, it would be advantageous to have a method and apparatus that takes into account at least some of the issues discussed above, as well as possibly other issues.